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Easily synthesized new porous K0.5VOPO4·1.5H2O cathode for aqueous zinc-ion batteries, including high output voltage and intercalation/conversion Zn2+storage mechanism.

Rearrangement sorting problems impact profoundly in measuring genome similarities and tracing historic scenarios of species. However, recent studies on genome rearrangement mechanisms disclosed a statistically significant evidence, repeats are situated at the ends of rearrangement relevant segments and stay unchanged before and after rearrangements.To reflect the principle behind this evidence, we propose flanked block-interchange, an operation on strings that exchanges two substrings flanked by identical left and right symbols in a string. The flanked block-interchange distance problem is formulated as finding a shortest sequence of flanked block-interchanges to transform a string into the other. We propose a sufficient and necessary condition for deciding whether two strings can be transformed into each other by flanked block-interchanges. This condition is linear time verifiable. Under this condition for two strings, we present a $\text{4}\,k$4k-approximation algorithm for the flanked block-interchange distance problem where each symbol occurs at most $k$k times in a string and a polynomial algorithm for this problem where each symbol occurs at most twice in a string. We show that the problem of flanked block-interchange distance is NP-hard at last.

General-purpose protein structure embedding can be used for many important protein biology tasks, such as protein design, drug design and binding affinity prediction. Recent researches have shown that attention-based encoder layers are more suitable to learn high-level features. Based on this key observation, we propose a two-level general-purpose protein structure embedding neural network, called ContactLib-ATT. On local embedding level, a biologically more meaningful contact context is introduced. On global embedding level, attention-based encoder layers are employed for better global representation learning. Our general-purpose protein structure embedding framework is trained and tested on the SCOP40 2.07 dataset. As a result, ContactLib-ATT achieves a SCOP superfamily classification accuracy of 82.4% (i.e., 6.7% higher than state-of-the-art method). On the same dataset, ContactLib-ATT is used to simulate a structure-based search engine for remote homologous proteins, and our top-10 candidate list contains at least one remote homolog with a probability of 91.9%.

Electronic structure defines the conductivity and ion absorption characteristics of a functional electrode, significantly affecting the charge transfer capability in batteries, while it is rarely thought to be involved in mesoscopic volume and diffusion kinetics of the host lattice for promoting ion storage. Here, we first correlate the evolution in electronic structure of the Mo6S8cathode with the ability to bound volume expansion and accelerate diffusion kinetics for high-performance aqueous Cu2+storage. Operandosynchrotron energy-dispersive X-ray absorption spectroscopy reveals that accumulative delocalized Mo 4d electrons enhance the Mo–Mo interaction with distinctly contracting and uniformizing Mo6clusters during the reduction of Mo6S8, which potently restrain lattice expansion and release space to promote Cu2+diffusion kinetics. Operandosynchrotron X-ray diffraction and comprehensive characterizations further validate the structural and electrochemical properties induced by the Cu2+intercalation electronic structure, endowing the Mo6S8cathode a high specific capacity with small volume expansion, fast ions diffusion, and long-term cycling stability.

Scintillation-based X-ray imaging can provide convenient visual observation of absorption contrast by standard digital cameras, which is critical in a variety of science and engineering disciplines. More efficient scintillators and electronic postprocessing derived from neural networks are usually used to improve the quality of obtained images from the perspective of optical imaging and machine vision, respectively. Here, we propose to overcome the intrinsic separation of optical transmission process and electronic calculation process, integrating the imaging and postprocessing into one fused optical–electronic convolutional autoencoder network by affixing a designable optical convolutional metasurface to the scintillator. In this way, the convolutional autoencoder was directly connected to down-conversion process, and the optical information loss and training cost can be decreased simultaneously. We demonstrate that feature-specific enhancement of incoherent images is realized, which can apply to multi-class samples without additional data precollection. Hard X-ray experimental validations reveal the enhancement of textural features and regional features achieved by adjusting the optical metasurface, indicating a signal-to-noise ratio improvement of up to 11.2 dB. We anticipate that our framework will advance the fundamental understanding of X-ray imaging and prove to be useful for number recognition and bioimaging applications.

Exploring stable and durable cathodes for cost-effective reversible aqueous batteries is highly desirable for grid-scale energy storage applications, but significant challenges remain. Herein, we disclosed an ultrastable Cu2+intercalation chemistry in mass-produced exfoliated NbS2nanosheets to build ultralong lifespan aqueous batteries with cost advantages. Anisotropic interplanar expansion of NbS2lattices balanced dynamic Cu2+incorporation and the highly reversible redox reaction of Nb4+/Nb(4−δ)+couple were illuminated by operando synchrotron X-ray diffraction and energy dispersive X-ray absorption spectroscopy, affording an extraordinary capacity of approximately 317 mAh g–1at 1 A g–1and a good stability of 92.2% capacity retention after 40000 cycles at 10 A g–1. Impressively, a budget NbS2||Fe hybrid ion cell involving an aqueous electrolyte/Fe-metal anode is established and provides a reliable energy supply of 225.4 Wh kg–1at 750 W kg–1, providing insights for building advanced aqueous battery systems for large-scale applications.

In situ X-ray spectroscopy and chemometrics approach to identify the evolution of local atomic and charge compensation in Li2RuxMn1−xO3.

Engineering multifunctional superstructure cathodes to conquer the critical issue of sluggish kinetics and large volume changes associated with divalent Zn-ion intercalation reactions is highly desirable for boosting practical Zn-ion battery applications. Herein, it is demonstrated that a MoS2/C19H42N+(CTAB) superstructure can be rationally designed as a stable and high-rate cathode. Incorporation of soft organic CTAB into a rigid MoS2host forming the superlattice structure not only effectively initiates and smooths Zn2+transport paths by significantly expanding the MoS2interlayer spacing (1.0 nm) but also endows structural stability to accommodate Zn2+storage with expansion along the MoS2in-plane, while synchronous shrinkage along the superlattice interlayer achieves volume self-regulation of the whole cathode, as evidenced by in situsynchrotron X-ray diffraction and substantial ex situcharacterizations. Consequently, the optimized superlattice cathode delivers high-rate performance, long-term cycling stability (∼92.8% capacity retention at 10 A g–1after 2100 cycles), and favorable flexibility in a pouch cell. Moreover, a decent areal capacity (0.87 mAh cm–2) is achieved even after a 10-fold increase of loading mass (∼11.5 mg cm–2), which is of great significance for practical applications. This work highlights the design of multifunctional superlattice electrodes for high-performance aqueous batteries.

Rechargeable aqueous zinc ion batteries (AZIBs) are attracting extensive attention owing to environmental friendliness and high safety. However, its practical applications are limited to the poor Coulombic efficiency and stability of a Zn anode. Herein, we demonstrate a periodically stacked CuS-CTAB superlattice, as a competitive conversion-type anode for AZIBs with greatly improved specific capacity, rate performance, and stability. The CuS layers react with Zn2+to endow high capacity, while CTAB layers serve to stabilize the structure and facilitate Zn2+diffusion kinetics. Accordingly, CuS-CTAB shows superior rate performance (225.3 mA h g–1at 0.1 A g–1with 144.4 mA h g–1at 10 A g–1) and a respectable cyclability of 87.6% capacity retention over 3400 cycles at 10 A g–1. In view of the outstanding electrochemical properties, full batteries constructed with a CuS-CTAB anode and cathode (ZnxFeCo(CN)6and ZnxMnO2) are evaluated in coin cells, which demonstrate impressive full-battery performance.

Aqueous zinc batteries (AZBs) are considered promising candidates for large-scale energy storage systems because of their low cost and high safety. However, currently developed AZB cathodes always suffer from the intense charge repulsion of multivalent-ion and complex multiphase electrochemistry, resulting in an insufficient cycling life and impracticable high-sloping discharge profile. Herein, we found that the synthesized ultrathin Bi2O2Se nanosheets can effectively activate stable protons storage in AZBs rather than large zinc ions. This proton-dominated cathode provides an ultraflat discharge plateau (72% capacity proportion) and exhibits long-term cyclability as 90.64% capacity retention after 2300 cycles at 1 A g–1. Further in situsynchrotron X-ray diffraction, ex situX-ray photoelectronic spectroscopy, and density functional theory confirm the energy storage mechanism regarding the highly reversible proton insertion/extraction process. Benefiting from the proton-dominated fast dynamics, reliable energy supply (>81.5% discharge plateau capacity proportion) is demonstrated at a high rate of up to 10 A g–1and in the frozen electrolyte below −15 °C. This work provides a potential design of high-performance electrode materials for AZBs.

Notorious shuttle effect and sluggish redox kinetics as major bottlenecks have nowadays hindered the commercial implementation of lithium–sulfur batteries. The activity design of catalysts has attracted increasing attention in this realm thus far. Herein, we devise a Co-based electrocatalytic tandem (Co–N–P) encompassing (N,P)-coordinated Co single atoms and Co2P nanoparticles for guiding the dual-directional sulfur evolution reactions. Such a Co–N–P tandem synergizes high atom utilization, large catalyst loading, and smooth charge migration, thereby resulting in high activity for dictating the Li2S nucleation and decomposition. As a result, the full cell incorporating the Co–N–P-modified separator harvests 0.1 % capacity decay after 500 cycles at 1.0 C. In addition, a favorable areal capacity output of 4.2 mAh/cm2is obtained under a sulfur loading of 5.3 mg/cm2. We anticipate that this work would offer insight into the hybrid catalyst design affording high activity and stability for emerging energy applications.

Nickel-rich layered oxides, as the most promising commercial cathode material for high-energy density lithium-ion batteries, experience significant surface structural instabilities that lead to severe capacity deterioration and poor thermal stability. To address these issues, radially aligned grains and surface LixNiyWzO-like heterostructures are designed and obtained with a simple tungsten modification strategy in the LiNi0.91Co0.045Mn0.045O2cathode. The formation of radially aligned grains, manipulated by the WO3modifier during synthesis, provides a fast Li+diffusion channel during the charge/discharge process. Moreover, the tungsten tends to enter into the lattice of the primary particle surface, and the armor-type tungsten-rich heterostructure protects the bulk material from microcracks, structural transformations, and surface side reactions. First-principles calculations indicate that oxygen is more stable in the surface tungsten-rich heterostructure than elsewhere, thus triggering an improved surface structural stability. Consequently, the 2 wt % WO3-modified LiNi0.91Co0.045Mn0.045O2(NCM@2W) material shows outstanding prolonged cycling performance (capacity retention of 80.85% after 500 cycles) and excellent rate performance (5 C, 188.4 mA h g–1). In addition, its layered-to-rock salt phase transition temperature is increased by 80 °C compared with that of the pristine cathode. This work provides a novel surface modification approach and an in-depth understanding of the overall performance enhancement of nickel-rich layered cathodes.

Developing a precise and reproducible bandgap tuning method that enables tailored design of materials is of crucial importance for optoelectronic devices. Towards this end, we report a sphere diameter engineering (SDE) technique to manipulate the bandgap of two-dimensional (2D) materials. A one-to-one correspondence with an ideal linear working curve is established between the bandgap of MoS2and the sphere diameter in a continuous range as large as 360 meV. Fully uniform bandgap tuning of all the as-grown MoS2crystals is realized due to the isotropic characteristic of the sphere. More intriguingly, both a decrease and an increase of the bandgap can be achieved by constructing a positive or negative curvature. By fusing individual spheres in the melted state, post-synthesis bandgap adjustment of the supported 2D materials can be realized. This SDE technique, showing good precision, uniformity and reproducibility with high efficiency, may further accelerate the potential applications of 2D materials.

The prediction of RNA structure with pseudoknots is NP-hard problem. According to minimum free energy models and computational methods, we investigate the RNA pseudoknotted structures and their characteristics. The paper presents an efficient algorithm for predicting RNA structures with pseudoknots, and the algorithm runs in O(n3) time and O(n2) space. The experimental tests in Rfam10.1 and PseudoBase indicate that the algorithm is more effective and precise, and the algorithm can predict arbitrary pseudoknots. And through our research, we can draw that there exists an 1 + ε(ε> 0) polynomial time approximation scheme in searching maximum number of stackings, and we give the proof of the approximation scheme in RNA pseudoknotted structures.

SnSe is a promising anode material in sodium-ion batteries (SIBs) due to its high theoretical capacity (780 mA h g−1) and natural abundance. Herein, we report SnSe nanoplates vertically grown on nitrogen-doped carbon (SnSe/NC) with strong Sn-C bonding for high-performance anode in SIBs, which are synthesized by a facial cation-exchange strategy. The vertically grown SnSe nanoplates with large interplanar spacing (0.58 nm), strong electronic coupling of Sn-C bonding between SnSe and NC facilitate the fast electron/ion transfer, enabling high pseudocapacitive Na-ion storage and enhanced power capability. Density functional theory calculations demonstrate that the presence of N heteroatoms in NC matrix has a pivotal influence on the formation of Sn-C bonding to stabilize the SnSe/NC structure. Moreover, the SnSe nanoplates of SnSe/NC exhibits low interlayer Na+diffusion barrier (0.1 eV) and low energy barrier (0.14 eV/uc) from discharged product to pristine SnSe/NC, implying the fast Na+diffusion capability and good reversibility. Consequently, the SnSe/NC exhibits large capacities of 723 and 88 mA h g−1at 0.025 and 20 A g−1, respectively, and 82% capacity retention for over 200 cycles at 2 A g−1, boosting promising applications in high-performance SIBs.

The metal-free synthesis of graphene on single-crystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed, single-crystal silicon substrate using metal-free, ambient-pressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates.

Two-dimensional (2D) antimonene is a promising anode material in sodium-ion batteries (SIBs) because of its high theoretical capacity of 660 mAh g–1and enlarged surface active sites. However, its Na storage properties and sodiation/desodiation mechanism have not been fully explored. Herein, we propose the sodiation/desodiation reaction mechanism of 2D few-layer antimonene (FLA) based on results acquired by in situsynchrotron X-ray diffraction, ex situselected-area electron diffraction, and theoretical simulations. Our study shows that the FLA undergoes anisotropic volume expansion along the a/bplane and exhibits reversible crystalline phase evolution (Sb ⇋ NaSb ⇋ Na3Sb) during cycling. Density-functional theory calculations demonstrate that the FLA has a small Na-ion diffusion barrier of 0.14 eV. The FLA delivers a larger capacity of 642 mAh g–1at 0.1 C (1 C = 660 mA g–1) and a high rate capability of 429 mAh g–1at 5 C and maintains a stable capacity of 620 mA g–1at 0.5 C with 99.7% capacity retention from the 10th to the 150th cycle. Considering the 660 mAh g–1theoretical capacity of Sb, the electrochemical utilization of Sb atoms of FLA is as high as 93.9% at a rate of 0.5 C for over 150 cycles, which is the highest capacity and Sb utilization ratio reported so far. Our study discloses the Na storage mechanism of 2D FLA, boosting promising applications of 2D materials for advanced SIBs.

Presently, porous materials have become essential to many technological applications. In this account, 3-dimensional skeleton composite materials consisting of a core–shell amorphous porous carbon/multilayer graphene are synthesized by chemical vapor deposition on Ni foam using a facile one-step growth method. The data suggest that these composites have not only outstanding electrical and mechanical properties of the multilayer graphene but also the mesoporous characteristics of the amorphous carbon. Moreover, the composited carbon materials perfectly inherit the macroporous structure of Ni foam, and the amorphous carbon core in the skeleton serves as a cushion to buffer the volume variation after the removal of Ni. The carbon composites reveal ultralow density (4.45 mg cm–3) and high conductivity (45 S cm–1), essentially issued from the perfectly preserved structural integrity of graphene. The novel carbon composites can be used as anodes for lithium ion batteries. After these carbon composites are incorporated with NaBiO3, superior electrochemical activities above 2 V can be achieved with a discharge capacity of ∼300 mAh g–1.

Protons can penetrate through single-layer graphene, but thicker graphene layers (more than 2 layers), which possess more compact electron density, are thought to be unfavorable for penetration by protons at room temperature and elevated temperatures. In this work, we developed an in situsubsecond time-resolved grazing-incidence X-ray diffraction technique, which fully realizes the real-time observation of the thermal proton interaction with the graphene layers at high temperature. By following the evolution of interlayer structure during the protonation process, we demonstrated that thermal protons can transport through multilayer graphene (more than 8 layers) on nickel foil at 900 °C. In comparison, under the same conditions, the multilayer graphenes are impermeable to argon, nitrogen, helium, and their derived ions. Complementary in situtransport measurements simultaneously verify the penetration phenomenon at high temperature. Moreover, the direct transport of protons through graphene is regarded as the dominant contribution to the penetration phenomenon. The thermal activation, weak interlayer interaction between layers, and the affinity of the nickel catalyst may all contribute to the proton transport. We believe that this method could become one of the established approaches for the characterization of the ions intercalated with 2D materials in situand in real-time.

Abstract: Block-move is one of the popular operations for genome rearrangement. A short block-move is an operation on a permutation that moves an element at most two positions away from its original position. Heath and Vergara investigated the problem of finding a minimum-length sorting sequence of short block-moves for a given permutation and devised a 4/3-approximation algorithm. In this paper, we present a new 14/11-approximation algorithm for this problem. Firstly, we devise an exact polynomial time algorithm for sorting a special kind of sub-permutations called umbrella; then we split the permutation into a series of related umbrellas and sort them greedily. We obtain a new lower bound of the short block-move distance by exploiting the properties of five kinds of sub-permutations. After some complicated analysis, we prove that the approximation ratio of the new algorithm is at most 14/11.

Sequence alignment reveals the relations between the characters in different sequences, and there are the reverse complement relations between the characters in DNA double strand. We introduce sequence alignment to the field of DNA computing, propose the definitions of complement alignment and reverse complement alignment, give a method of computing the scores of complement alignment and reverse complement alignment, and devise a DNA encoding method and the corresponding DNA algorithm for the Minimum Spanning Tree (MST) problem by means of reverse complement alignments. Our work enriches the theory of DNA computing and extends the range of DNA computing to solve optimisation problems.

Niacin is a widely used lipid-regulating agent in dyslipidemic patients. Previously, we have shown that niacin inhibits triacylglycerol synthesis. In this report, using HepG2 cells, we have examined the effect of niacin on the mRNA expression and microsomal activity of diacylglycerol acyltransferase 1 and 2 (DGAT1 and DGAT2), the last committed but distinctly different enzymes for triglyceride synthesis. Addition of niacin to the DGAT assay reaction mixture dose-dependently (0–3 mM) inhibited DGAT activity by 35–50%, and the IC50was found to be 0.1 mM. Enzyme kinetic studies showed apparent Kmvalues of 8.3 μM and 100 μM using [14C]oleoyl-CoA and sn-1,2-dioleoylglycerol as substrates, respectively. A decrease in apparent Vmaxwas observed with niacin, whereas the apparent Kmremained constant. A Lineweaver-Burk plot of DGAT inhibition by niacin showed a noncompetitive type of inhibition. Niacin selectively inhibited DGAT2 but not DGAT1 activity. Niacin inhibited overt DGAT activity. Niacin had no effect on the expression of DGAT1 and DGAT2 mRNA.

Cerebellar granule cell neurons undergo apoptotic cell death when subjected to serum-free conditions at physiological concentrations of potassium (5 mM). Protein kinase C (PKC) is known to play a role in preventing neuronal apoptosis under trophic factor deprivation, but its role in protecting cerebellar neurons from cell death under conditions of low potassium is unknown. This study sought to determine the involvement of PKC in neuronal survival and to determine if PKC regulated the phosphatidylinositol 3-kinase (PI 3-K)/Akt pathway in low physiologic concentrations of potassium. Incubation with a pan-PKC inhibitor, Ro-31-8220 (2 μM), or a specific PKCα inhibitor, Gö6976, protected cerebellar granule cell neurons from low potassium-mediated cell death. In contrast, phorbol ester (TPA, 100 nM), a PKC activator, increased cell death. Incubation with, Ro-31-8220 rescued neurons from cell death induced by the PI 3-K inhibitor, LY294002, suggesting that Ro-31-8220 may affect Akt phosphorylation. Western blot analysis showed that serum-free, low potassium conditions decreased Akt phosphorylation, which was exacerbated by treatment with LY294002. In contrast, PKC inhibitors, Gö6976 or Ro-31-8220, increased Akt phosphorylation approximately two and fourfold, respectively, in low potassium conditions. Because Akt activation appears to be critical in promoting neuronal survival under these culture conditions, increased Akt phosphorylation brought about by inhibiting PKC promotes neuronal survival.

Delineating the mechanisms of survival pathways that exist in neurons will provide important insight into how neurons utilize intracellular proteins as neuroprotectants against the causes of acute neurodegeneration. We have employed cultured rat cerebellar granule cells as a model for determining the mechanisms of these intraneuronal survival pathways. Glutamate has long been known to kill neurons by an N-methyl-d-aspartate (NMDA) receptor-mediated mechanism. Paradoxically, subtoxic concentrations of NMDA protect neurons against glutamate-mediated excitotoxicity. Because NMDA protects neurons in physiologic concentrations of glucose and oxygen, we refer to this phenomenon as physiologic preconditioning. One of the major mechanisms of NMDA neuroprotection involves the activation of NMDA receptors leading to the rapid release of brain-derived neurotrophic factor (BDNF). BDNF then binds to and activates its cognate receptor, receptor tyrosine kinase B (TrkB). The efficient utilization of these two receptors confers remarkable resistance against millimolar concentrations of glutamate that kill more than eighty percent of the neurons in the absence of preconditioning the neurons with a subtoxic concentration of NMDA. Exactly how the neurons mediate neuroprotection by activation of both receptors is just beginning to be understood. Both NMDA and TrkB receptors activate nuclear factor kappaB (NF-?B), a transcription factor known to be involved in protecting neurons against many different kinds of toxic insults. By converging on survival transcription factors, such as NF-?B, NMDA and TrkB receptors protect neurons. Thus, crosstalk between these very different receptors provides a rapid means of neuronal communication to upregulate survival proteins through release and transcriptional activation of messenger RNA.

The paper briefly reviews NP-hard optimization problems and their inapproximability. The hardness of solving CLIQUE problem is specifically discussed. A dynamic-programming algorithm and its improved version for CLIQUE are reviewed and some additional analysis is presented. The analysis implies that the improved algorithm, HEWN (hierarchical edge-weighted network), only provides a heuristic or useful method, but cannot be called a polynomial algorithm.

ABSTRACTAnaplasma marginaleis a tick-transmitted pathogen of cattle closely related to the human ehrlichiae, Ehrlichia chaffeensisand the agent of human granulocytic ehrlichiosis (HGE). These pathogens have in common a structurally conserved outer membrane protein (OMP) designated the major surface protein 2 (MSP-2) in A. marginaleand HGE and OMP-1 in E. chaffeensis. Protective immunity against ehrlichial pathogens is believed to require induction of gamma interferon (IFN-γ) and opsonizing immunoglobulin (Ig) subclasses directed against OMP epitopes that, in concert, activate macrophages for phagocytosis and killing. Because interleukin-12 (IL-12) acts as an adjuvant for protein immunization to induce IFN-γ and protective immunity against intracellular pathogens, we hypothesized that as an adjuvant with MSP-2, IL-12 would augment type 1 recall responses to A. marginale. IL-12 was coadsorbed with MSP-2 to alum and shown to significantly enhance IFN-γ production by lymph node cells (LNC) and LNC-derived CD4+T-cell lines from immunized calves following recall stimulation with A. marginale. LNC proliferation and IL-2 production were also enhanced in IL-12-treated calves. Elevated recall proliferative responses by peripheral blood mononuclear cells were still evident 9 months after immunization. Serum IgG levels were consistently increased in IL-12 immunized calves, predominantly due to higher IgG1 responses. The results support the use of IL-12 coadsorbed with OMP of ehrlichial pathogens in alum to amplify both antibody and type-1 cytokine responses important for protective immunity.

ABSTRACTMajor surface proteins of Anaplasma marginaleare vaccine candidates. We recently demonstrated that immunization of calves with outer membranes of the Florida strain ofA. marginaleresulted in protective immunity that correlated with a memory CD4+T-lymphocyte response specific for major surface protein 1 (MSP-1), MSP-2, and MSP-3 (W. C. Brown, V. Shkap, D. Zhu, T. C. McGuire, W. Tuo, T. F. McElwain, and G. H. Palmer, Infect. Immun. 66:5406–5413, 1998). As immunogens, these proteins have been shown to induce complete or partial protection against homologous challenge. To further define the T helper (Th) cell response to these and other A. marginaleantigens and to determine conservation of Th cell epitopes among genetically distinct A. marginalestrains, Th cell clones obtained prior to challenge from three immunized calves were characterized for antigen-specific responses. Nine distinct antigenic profiles were defined by 11 Th cell clones derived by stimulation with the Florida strain. Several clones responded to MSP-2, MSP-3, or both. All of these MSP-2- or MSP-3-specific clones and the majority of other clones that did not respond to MSPs recognized all bovine blood-passaged strains ofA. marginale. These results demonstrate conservation of certain Th cell epitopes between MSP-2 and MSP-3 and show that Th cell epitopes in MSP-2, MSP-3, and undefined antigens are conserved among strains of A. marginale. Of seven clones that responded to the blood-passaged Virginia strain, two did not recognize antigen prepared from this strain cultured in tick cells, suggesting differences in the antigenic composition between these stages. Analysis of the cytokines expressed by the Th cells revealed that all clones expressed gamma interferon and tumor necrosis factor alpha, and most coexpressed interleukin-4. Our results provide a rationale for identifying Th cell epitopes conserved among different strains of A. marginalefor inclusion in a nucleic acid or recombinant protein vaccine.

ABSTRACTProtective immunity against the ehrlichial pathogenAnaplasma marginalehas been hypothesized to require induction of immunoglobulin G2 (IgG2) antibody against outer membrane protein epitopes and coordinated activation of macrophages for phagocytosis and killing. In the present study, cell-mediated immune responses, including induction of IgG isotype switching, were characterized in calves immunized with purified outer membranes of the Florida strain of A. marginale. Importantly, these calves were subsequently shown to be protected upon experimental challenge with the Florida strain, and calves which developed the highest IgG2 titers were completely protected against infection. Peripheral blood mononuclear cells (PBMC) obtained after immunization proliferated strongly in response to both whole A. marginalehomogenates and purified outer membranes, and this responsiveness persisted until the time of challenge. Responding cells were shown to be CD4+T cells, and CD4+T-cell lines cultured for 2 to 4 weeks also proliferated specifically in response to A. marginaleand produced high titers of gamma interferon. The helper T-cell response included recognition of conserved epitopes, as PBMC proliferation was stimulated by the homologous Florida strain, four genetically distinct A. marginalestrains, and Anaplasma ovis. The outer membrane proteins stimulating the PBMC responses in protected calves included major surface proteins (MSPs) MSP-1, MSP-2, and MSP-3, which were previously shown to induce partial protection against infection. These studies demonstrate, for the first time, potent helper T-cell responses in cattle protectively immunized with outer membranes against A. marginalechallenge and identify three MSPs that are recognized by immune T cells. These experiments provide the basis for subsequent identification of the helper T-cell epitopes on MSP-1, MSP-2, and MSP-3 that are needed to evoke anamnestic antibody and effector T-cell responses elicited by protein or nucleic acid immunization.

Electrocatalytic N2oxidation (NOR) into nitrate is a potential alternative to the emerging electrochemical N2reduction (NRR) into ammonia to achieve a higher efficiency and selectivity of artificial N2fixation, as O2from the competing oxygen evolution reaction (OER) potentially favors the oxygenation of NOR, which is different from the parasitic hydrogen evolution reaction (HER) for NRR. Here, we develop an atomically dispersed Fe-based catalyst on N-doped carbon nanosheets (AD-Fe NS) which exhibits an exceptional catalytic NOR capability with a record-high nitrate yield of 6.12 μ mol mg–1h–1(2.45 μ mol cm–2h–1) and Faraday efficiency of 35.63%, outperforming all reported NOR catalysts and most well-developed NRR catalysts. The isotopic labeling NOR test validates the N source of the resultant nitrate from the N2electro-oxidation catalyzed by AD-Fe NS. Experimental and theoretical investigations identify Fe atoms in AD-Fe NS as active centers for NOR, which can effectively capture N2molecules and elongate the N≡N bond by the hybridization between Fe 3d orbitals and N 2p orbitals. This hybridization activates N2molecules and triggers the subsequent NOR. In addition, a NOR-related pathway has been proposed that reveals the positive effect of O2derived from the parasitic OER on the NO3–formation.

Summary: CTRD is a software for computing translocation distance between genomes. It takes two genomes as its input and tests whether one genome can be transformed into the other. If possible, it computes the translocation distance between two genomes, and gives the translocation operation serial. We adopt the fastest known O(n2log n) algorithm. Our contributions include (1) give a necessary and sufficient condition to ensure that one genome can be transformed into the other for translocation operations, and (2) develop a software using the fastest known O(n2log n) algorithm. Availability: Free from http://www.cs.cityu.edu.hk/~lwang/software/Translocation/ subject to copyright restrictions.